JPS6354218B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a method for resin-sealing resin-sealed electronic components, such as semiconductor devices such as ICs and LSIs. The purpose of this is to enable shortening, reduce deformation of the electrode leads (thin metal wires) of the electronic component to be sealed, and further increase the utilization rate of the resin material.

Transfer molding has generally been used as a method for resin-sealing resin-sealed electronic components, such as resin-sealed semiconductor devices. First, regarding this method,
This will be explained based on FIGS. 1 and 2.

1 is the resin portion remaining in the resin supply section, 2 is the resin portion remaining in the resin transfer path (runner),
These are all parts that do not become products. The resin passes through the gate 3 and fills the cavity 4 in which the semiconductor element is housed.

Note that 5 is a lead frame. Furthermore, the mechanism of transfer molding will be briefly explained with reference to FIG. Taking epoxy resin as an example, a preheated resin tablet (pressure molded product) is introduced into the resin material injection hole 7 of the upper mold 6 heated to 150° to 190°C, and when the plunger 8 pressurizes and injects it, The epoxy resin softens and becomes a fluid that flows through the runners in the mold.

A narrow gap called a gate 3 is formed on the side surface of the runner 2, and this gate 3 communicates with a cavity 4. The cavity 4 consists of a space cut into upper and lower molds, and a lead frame 5 on which a semiconductor element is mounted is fixed inside the cavity 4 under pressure by the upper and lower molds. The mold is provided with a plurality of cavities 4, and resin is press-fitted to fill these cavities 4. After press-fitting,
The mold is held in place for several minutes until the resin hardens. After that, the mold is opened and the product in the state shown in Figure 1 is taken out. The above is the mechanism of the transfer molding method.

The problems with this method are: 1. There are many runner parts, and the utilization rate of resin in the product is low.

2. In order to improve mass production, a large number of molds are sealed at once, which requires advanced skills to maintain and control precision over the entire surface of the mold, making automation and unmanned operation difficult.

3 In order to improve mass production, the larger the mold, the longer the sealing time.

4 The thin metal wire 11 connecting between the semiconductor element substrate 9 and the tip 10' of the external lead wire 10 shown in FIG. 3 is deformed when filling the cavity with resin to form the molded resin shell 12. Or the wire may break, causing quality problems such as shorts.

It is summarized in For this reason, human skills were required to maintain and manage the accuracy of the mold, making automation difficult and making it a key process for continuous production in the semiconductor element assembly process.

The present invention provides a resin sealing method that can eliminate the above problems.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 4, first, the means for preheating the comb material 5 in which the semiconductor device is incorporated and the means for supplying it to the sealing mold will be explained. 19 is a magazine stocker in which the com materials 5 are stacked and stored at a constant pitch;
20 is a motor; 21 is a comb material transfer loader that can move vertically and horizontally; 22 is a comb material pull-out pin attached to the comb material transfer loader 21; 23 is a preheat rail incorporating a heater 24;
Reference numeral 5 denotes a comb material chucking device mounted on the comb material transfer loader 21.

In the above configuration, the comb material transfer loader 21
As the magazine stocker 19 moves vertically and horizontally, the uppermost comb material 5a of the magazine stocker 19 is pulled out onto the preheat rail 23 by the pull-out pin 22. At the same time, the comb material 5 already on the preheat rail 23 and heated by the heater 24
b is supplied to the lower mold 17 by the comb material chucking device 25. Magazine stock car 19
After the above operations are completed, the comb material 5b is raised by a predetermined pitch by the motor 20, and the comb material 5b drawn out onto the preheat rail 23 is immediately heated by the heater 24 and prepared for the next cycle. Therefore, by the operation of the comb material transfer loader 21, the comb material 5a is pulled out from the magazine case 19,
Two operations of supplying the preheated comb material 5b to the lower mold 17 can be performed simultaneously. Further, there is an effect that the comb material 5b can be prepared for heating during sealing molding. In this embodiment, when the comb material 5 is supplied, it is pulled out from the magazine stocker 19 onto the preheat rail 25 using the comb pull-out pin 22, but it may also be directly fed onto the preheat rail 23 using a conveyor or the like.

Next, the molding means will be explained.

6 is the upper mold, 17 is the lower mold and the heating heater 2
It has a built-in 4'. 26 is a lower die plate that fixes the lower die plate 17; 27 is a mold clamping cylinder that provides thrust to the lower die plate 26; 28 is a tie bar shaft, one end of which is fixed to the upper die plate 29; Perform sliding guide.

The upper mold 6 has resin injection holes 16 and heaters 24' corresponding to the number of semiconductor elements assembled in the comb material 5c, and is fixed to an upper die plate 29. Further, 30 is a molded cylinder that provides thrust to the plunger 9.

In the above configuration, when the preheated comb material 5c is supplied to the lower mold 17, the lower mold 17 rises while further heating the comb material 5c by the heater 24', and the lower mold 17 and the upper mold 6 is dotted and the mold is tightened.

Next, the resin material pellets 18 are charged into the resin material injection hole 16 of the upper mold 6, the plunger 9 descends, and the melted resin material heated by the heating heater 24'' is injected into the cavity under pressure. , sealing molding is performed.

Next, a take-out means for taking out the encapsulated comb material 5c (hereinafter referred to as comb molded product) from the mold;
Also, a means for taking out the comb molded product 5d from which the gate residue has been removed will be explained. 31 is the lower mold 17
Similarly, 32 is a chucking device for taking out the comb molded product 5d from which the gate residue has been removed, and 33 is a rail for receiving the molded comb material 5d taken out from the lower mold 17. , 34 is a take-out loader that moves the chucking devices 31, 32 vertically and horizontally. In the above configuration, after the sealing molding is completed and the lower mold 17 is lowered, the take-out loader 34 moves into the mold, grips the comb molded product 5c with one chuck device 31, and removes the rail with the other chuck device 32. The comb molded product 5d from which the gate residue has been removed is grasped on 33 and taken out. Therefore, one operation of the take-out loader 34 can simultaneously take out the comb molded product 5c and the comb molded product 5d from which the gate residue has been removed.

Next, the means for supplying the resin pellets 18 will be explained. 35 is a hopper for storing a large number of resin pellets 18; 36 is a fixed pipe chute with both ends open; 37 is a disk with a hole capable of intermittent rotation; the hole 38 matches the lower opening of the pipe chute 36. It's becoming like that. 39 is a supply block which is movable by external power and guides the plurality of resin material pellets 18, and 40 is a drive cylinder. In the above configuration, the hopper 35 is moved up and down by the drive cylinder 40, and the hopper 35 is moved vertically by the drive cylinder 40.
The resin pellet 18 in 5 is the pipe chute 36
will be inserted aligned with. The resin pellets 18 are separated one by one by a disk with holes 37 and sent to a supply block 39. When a predetermined number of resin pellets 18 are guided to the supply block 39, the supply block 39
is moved and the resin material injection hole 1 of the upper mold 6 is moved.
6, and the resin pellets 18 are fed all at once into the resin material feeding hole 16 at a predetermined time. By performing the individual operations described above continuously and cyclically, this device automatically and continuously performs everything from supplying the comb material 5 and resin pellets 18 to sealing molding and taking out the comb molded product 5c. This makes it possible.

Note that FIG. 5 is a partial cross-sectional view showing in more detail the structure of the upper and lower mold parts shown in FIG. 4. In this figure, a lead frame 5 is located between an upper mold 6 and a lower mold 17 and is connected to the cavity 4. Resin material injection hole 16 provided in the upper and lower molds 6
A resin material pellet 18 is inserted inside, and a plunger 9 is located above the resin material input hole 16.
is arranged so that it can move up and down. The resin material pellets 18 are a thermosetting resin, and are in an amount sufficient to fill one cavity 4. Resin material pellets 1 thrown into the resin material injection hole 16
8 is melted by the heat of the heated molds 6 and 17, and is press-fitted into the cavity 4 by the pressing force of the plunger 9.

FIG. 6 is an enlarged view of a part of the lead frame 5 after resin sealing is completed using the resin sealing mold shown in FIG. 5, and FIG. 7 is a view showing the whole. The resin residue 14 at the gate portion and the resin residue 13 within the supply section are connected to the molded resin outer shell 15 .

As described above, according to the present invention, efficiency for automation is improved by charging and distributing resin pellets in a mold-clamped state, and by simultaneously inserting each plunger by a single drive cylinder, processing is improved. It is possible to eliminate pressure variations and reduce costs, and furthermore, the entire process greatly contributes to continuous integrated production of semiconductor device assembly processes.

Although a single in-line type semiconductor device was molded in the example, it can be used not only for resin encapsulation of a dual-in-line type semiconductor device but also for other resin encapsulation type electronic components having a similar lead arrangement. It can also be implemented at any time.

[Brief explanation of drawings]

Figure 1 is a plan view showing the state of a semiconductor device immediately after resin encapsulation using the conventional transfer molding method;
The figure is a diagram for explaining the mechanism of transfer molding in the conventional method, Figure 3 is a diagram for explaining the internal state of a resin-sealed semiconductor device, and Figure 4 is a diagram for explaining the internal state of a resin-sealed semiconductor device. An overall perspective view showing one embodiment,
FIG. 5 is a partial sectional view of an embodiment of a resin molding die in the resin sealing device of the present invention, and FIG. 6 shows a part of a lead frame resin-sealed with the resin sealing device of the present invention. FIG. 7 is an enlarged perspective view and a plan view showing the overall shape of a lead frame resin-sealed with the resin-sealing device of the present invention. 4...Cavity, 6, 17...Resin sealing mold, 16...Resin pellet injection hole, 23...Transporting means, 24', 24''...Heating device, 31...
Retrieval means, 39...supply means.

Claims (1)

[Claims] 1. A step of preheating the components of a plurality of electronic components, a step of arranging the components into each cavity of a sealing mold, and a step of separating a large number of resin pellets one by one and sequentially supplying them to fixed positions. and a step of receiving the resin pellets supplied to the fixed position one by one, holding a plurality of pellets aligned corresponding to each cavity of the sealing mold, and waiting outside the sealing mold. , a step of clamping the sealing mold; and with the sealing mold being clamped, moving a group of the resin pellets that are lined up and waiting together to separate each of the sealing molds. distributing the resin material into each resin material input hole through which the plunger passes, simultaneously inserting each of the plungers into each of the resin material input holes by a single drive cylinder, and independently filling each cavity with molten resin; A method for resin-sealing an electronic component, comprising the steps of thermosetting, taking out the resin-sealed component from the sealing mold, and removing resin residue from the component.